This invention relates to novel aldehyde-containing synthetic heteropolysaccharides and a process for their preparation.
Polysaccharide compositions have been utilized in many diverse industrial applications, for example, as thickeners, adhesives, sizing agents, etc. Polysaccharides such as starch and cellulose, which have been modified to contain aldehyde groups, have found use particularly in the paper and textile industries.
Both oxidative and non-oxidative methods have been employed to introduce aldehyde groups onto polysaccharides. Oxidative methods which have been used include treating with periodic acid, periodates, alkali metal ferrates, or alkali aetal bromites, as described, for example, in U.S. Pat. No. 3,086,969 (issued Apr. 23, 1963 to J. Slager); U.S. Pat. No. 3,553,193 (issued Jan. 5, 1971 to D. LeRoy et al.); and U.S. Pat. No. 3,632,802 (issued Jan. 4, 1972 to J. BeMiller et al.). Non-oxidative methods which have been used include the reaction of a polysaccharide with an aldehyde-containing reagent as described in U.S. Pat. No. 3,519,618 (issued July 7, 1970 to S. Parmerter) and U.S. Pat. No. 3,740,391 (issued June 19, 1973 to L. Williams et al.).
Polygalactomannan gums (i.e. guar gum) and other natural galactose-containing polymers modified to possess aldehyde groups are useful as crosslinking agents and have been employed in various film-forming applications as adhesives or binding agents in self-sustaining films. Such aldehyde gum derivatives can be prepared by similar oxidative and non-oxidative methods to those mentioned above or, as described in U.S. Pat. No. 3,297,604 (issued Jan. 10, 1967 to F. Germino), polygalactomannans and other natural polysaccharides containing galactose configurations at the C.sub.4 position (i.e., talose) may be selectively oxidized at the C.sub.6 position of the saccharide unit by the enzyme galactose oxidase in order to yield aldehyde groups.
While commercially useful polysaccharide aldehydes have been obtained by various oxidative and non-oxidative methods, there is a continual demand to meet a broad industrial need for new polysaccharide compositions with unique rheological properties which also possess the aldehyde functionality.
It is therefore the object of the present invention to provide novel aldehyde-containing heteropolysaccharides, the polysaccharides being capable of undergoing crosslinking reactions alone or with other organic compounds. None of the above references disclose or suggest the products of the present invention.